Blinds for building openings, eg windows, doors and the like, may be operated either simply down and up, in the case of eg. roller blinds, or in the case of eg. vertical shade panels, the vertical shade panels may be rotated open or closed.
The control elements for these blind operations are usually in the form of an endless cord or chain. The control element simply hangs down along one side of the building opening, in an endless loop.
Other forms of blinds and window coverings may also be operated by means of an endless control element hanging in a loop.
In the past this system has been widely used, and experience was believed to be mainly satisfactory. In some cases a pendant weight was located on the loop, to assist in controlling it.
U.S. Pat. No. 4,932,456, inventor G Buxbaum, shows the usual form of blind chain and drive sprocket gear on the blind roller such as being standard in the art.
However safety considerations for some time have been forcing Government agencies seek further ways to restrict unsafe or unwanted access to the endless loop type of control element. The intent of these considerations has been mainly to prevent any chance that the element, may possibly create a hazard to children, or handicapped persons, or even pets.
In addition, by guiding and controlling the loop of the element, its operation by anyone becomes somewhat easier. The element is prevented from becoming twisted, or entangled with any other blinds controls, curtains or the like.
A simple pulley, fixed to the building fabric, and holding the loop in tension, was proposed to achieve this result. However such a pulley may become dislodged or loosened from the building to which it was attached. The guide pulley will then hang loose on the loop of the element, leaving the element uncontrolled, as before.
This led to accidents and unsafe conditions.
In other cases the pulley might have been installed incorrectly.
In U.S. Pat. No. 8,539,645 Inventor Mario M Marocco, there is shown a form of lock for a blind cord loop control in which a spring operated lock is used.
One of the problems in simply attaching the lower end of the loop to a pulley, is that the pulley, in whatever form it took, was attached to the window frame.
This meant that the customer who wished to adjust the blind had to stand close to the window to reach the chain. This may have been an inconvenience to many.
To prevent unsafe conditions and accidents it is now proposed that the element will be enclosed, blocked or shielded. Also, while rendering the system safe, preferably, the entire control system should not be actually anchored at its lower end to the window frame. It should be at least be somewhat moveable so that a customer could reach for the control without having to actually stand alongside the window.
U.S. Pat. No. 9,038,696, Aaron Lava, issued May 2015, shows a form of a rigid wand, holding the chain in tension, but otherwise the chain is fully exposed outside of the elongate or wand.
Adjustment of the chain was performed manually by simply grasping the chain exposed on one side or the other of the wand. This proposal still does not meet the problem of safety. Children, or even pets, could easily reach the chain exposed on each side of the wand.
A generally similar proposal is shown in U.S. Pat. No. 8,967,226, W D Vesta, issued Mar. 3, 2015. This proposal describes a rigid wand with pulleys top and bottom. The chain is substantially exposed along each side of the wand. It would not satisfy the requirements for safety.
Other arrangements are shown in U.S. Pat. No. 3,022,819, U.S. Pat. No. 5,752,558, U.S. Pat. No. 4,865,109, U.S. Pat. No. 6,192,293, U.S. Pat. No. 5,797,441, U.S. Pat. No. 5,845,696 and U.S. Pat. No. 4,865,109